1. Field of the Invention
The present invention relates to an indication structure for paper reserves, and in particular to an indication structure for paper reserves for use in an auto document feed apparatus that can provide an indication of paper reserves.
2. Description of the Prior Art
Following the upgraded rapidly of the industry, and the times of knowledge economic coming, such that the people using paper, files and messages in writing, which dealing with each other is more frequently; each type of the printers, copier, fax machines or other auto document feed apparatuses has been the major product for modern. Therefore, high added value, high resolution, light, low cost and fabrication convenience has been a major index for choosing.
Reference is made to FIG. 1, which illustrates an indication structure for paper reserves. The indication structure is adapted for use in accord with the prior art printers, copywriters, fax machines or auto document feed apparatuses. The indication structure for paper reserves has a support plate 11a for receiving paper. Support plate 11a contacts a spring 12a. The bottom of the support plate 11a has a hook 13a. The indication structure for paper reserves has a cord 1a and cord 1a has a first end and a second end, of which the first end links to the hook 13a. A support shaft 2a connects to a housing 14a of the auto document feed apparatus to allow the cord 1a to slide thereon. A slide 3a links to the second end of the cord 1a and slide 3a has a paper reserves indication pin 31a thereon to indicate the paper reserves. A guide shaft 4a is vertically arranged on the housing 14a of the auto document feed apparatus to allow the slide 3a to slide thereon. Support plate 1a compresses spring 12a and influences cord 1a to make slide 3a slide on the guide shaft 4a when the paper reserves in the support plate 11a of the auto document feed apparatus are high. As paper reserves decrease, the support plate 11a move gradually upward due to a force of the spring 3a, thereby causing the paper reserves indication pin 31a to indicate the amount of paper reserves.
Reference is made to FIG. 2, in which another indication structure for paper reserves adapted for auto document feed apparatus is illustrated in accord with the prior art. The indication structure for paper reserves has a support plate 1a′ for receiving paper and a lead screw 2a′ contacts the bottom of the support plate 1a′ to provide the support plate 1a′ for displacement upward or downward. A drive motor 3a′ is located on a side of the lead screw 2a′, the drive motor has at least one gear, to provide the lead screw 2a′ rotationally contacted therewith. A sensor 4a′ is located on a top side of the support plate 1a′ to provide pressure measurement. A feedback signal control module for drive motor 5a′ contacts the drive motor 3a′ or the sensor 4a′ electrically. Thereby, a program design of the feedback signal control module for drive motor 5a′ controls, while the paper do not reach the prediction high of paper, then paper do not touch the pressure sensor 4a′, at the same time the sensor 4a′ provides an electrical signal for the feedback signal control module for drive motor 5a′, (it is) dealt by the program design of the feedback signal control module for drive motor 5a′, to output a electrical signal to the drive motor 3a′ which driven the lead screw 2a′ to generate a displacement upward, making the paper arranges on the support plate 1a′ to reach and touch the pressure sensor 4a′, so that using the sensor 4a′ to detect the variation of the paper reserves, providing a electrical signal for the feedback signal control module for drive motor 5a′, dealt by the program design of the feedback signal control module for drive motor 5a′, to output a prediction known ideal value signal to the drive motor 3a′, thereby, to reach the purpose of automatic detecting paper reserves.
Moreover, the taught indication structure for paper reserves adapted for auto document feed apparatus as above description, (it is) providing a function of the paper reserves for showing or detecting, however, due to some manufacture technology limitations, more work pieces cause to be restricted of manufactured cost and fabrication on production line, and the mechanical complexity increases, too. Thereof, the qualities of taught manufacture technology limitations, so that the indication structure for paper reserves adapted for auto document feed apparatus can not be easily fabricated and fast maintained, thus the manufactured cost will be also increased.
Following the upgraded rapidly of the industry, such that the life of humans is also changed; fast, convenient, easy, light, handy and cheap is a code word of the modern. However, the taught indication structure for paper reserves adapted for auto document feed apparatus is unfavorable to repair, replace and maintain. Simultaneously, the manufactured cost and the difficulty of fabrication are increased, too. Today the requirements of indication structure for paper reserves adapted for auto document feed apparatus known in the prior art could not be reached.
Further, in according to the Kennedy's theorem or the Grashof's theorem of the Mechanical Engineering, we know that a multi-bar linkage system (generally above four-bar linkage) often has a plurality of instantaneous center or multi-degree of freedom thereon. Consequently, requires the higher precision for fabricating or arranging the mechanical system, the manufactured cost and the difficulty of fabrication increases, too.
Accordingly, as above description we knowing the indication structure for paper reserves adapted for auto document feed apparatus known in the prior art having exists a non-convenience and defect in using practically.
Therefore, the present invention is directed to an improved the indication structure for paper reserves adapted for auto document feed apparatus with the inventor's research hardly and the application of theorem having a reasonable design and lower manufactured cost thereon.